1. Field of the Invention
This invention relates to locking devices and more particularly to a new and improved locking device particularly useful in securing bicycles to substantially stationary structures such as poles, bars and stanchions, for example.
2. Description of the Prior Art
Bicycles and their use throughout the world are very old and rather popular. This popularity, although initially more so in the European countries and the Asian countries, has been increasing in the United States of America over the last few decades. Along with an increasing demand for bicycles, bicycles themselves have become much more complex and much more expensive. This large increase in both demand for bicycles and the cost of bicycles has lead to a large increase in bicycle theft. Bicycle theft has lead, in turn, to an increase in bicycle security and apparatus for securing and/or making secure unattended bicycles.
Various apparatus and locking mechanisms have been attempted for making secure unattended bicycles, without much degree of success.
Some locking mechanisms were integrated into the bicycle itself so as, when locked, to lock the steering mechanism in a turned position so that the bicycle could not be driven away without unlocking the installed or integrated lock. This approach was not very successful because, a bicycle being rather light in weight could very easily be carried away while locked and the lock on the steering mechanism could be removed and/or destroyed at a later time, with minimal damage to the bicycle.
It was found that a better approach was to secure or lock the unattended bicycle to some heavy, stable fixture such as a pole, stanchion, or some fixed structure which deterred unauthorized removal or theft of an unattended bicycle. Several different apparatus, or a combination of apparatus were, and still are, popular. One combination is a chain and lock; another is a cable and lock, the cable having loops on the ends. These combinations have been used with some success to secure a bicycle to some standing, heavy object, such as a pole or even, in some cases a reasonable fair size tree. This combination when used made it virtually impossible to carry off an unattended bicycle because of the stationary nature of the object to which the bicycle was secured. However, both chains and cables were subject to being cut by bolt cutters or hacksaws or other metal cutting or burning devices and the security offered by locking chains and/or cables was effectively reduced.
In order to defend against bolt cutters another locking mechanism was developed, i.e., a large, heavy U-shaped metal shackle with heavy, metal cross locking bars. These U-shaped shackles were made sufficiently large so that the shackle, when open, may pass around a relatively large fixed pole, bar or other pole-like object and secure the frame of the bicycle to such object. A bicycle lock typical of the U-shaped shackle and cross bar type is disclosed in U.S. Pat. No. 4,155,231; issued May 22, 1979.
However, this U-shaped shackle and cross bar bicycle lock, while providing a good defense against bolt cutters and hacksaws had other shortcomings. Because the U-shaped shackle of this type of locking mechanism was made large enough to pass around a range of pole diameters it was very often possible to insert a pry bar or lever bar between the shackle and the pole around which the shackle passes and spring open the shackle by applying a levered force against the shackle and/or locking mechanism. This, in many cases, forced open the securing mechanism without causing damage to the bicycle, leading to a successful theft.